The present invention relates to an arrangement of a rear-axle transmission in the region of a rear-axle support on the underside of the body of a passenger car, and, more particularly, to an arrangement in which the transmission is flexibly supported on the input side at the rear axle support and at the output side at two spaced fastening points in a transverse direction of the vehicle.
An arrangement of a rear-axle transmission provided in the Mercedes-Benz Model 190 has the output-side fastening points of the rear-axle transmission provided on the rear cross member of the rear-axle support and its input-side mounting firmly bolted on the front cross member.
It is an object of the invention to further improve the good driving comfort and handling performance with the suspension of the rear-axle transmission.
The foregoing object has been achieved by forming output-side fastening points as supported bearings fixed to the body independently of the rear-axle support.
By virtue of the rear-axle transmission being supported flexibly and independently of the rear-axle support, at least on the output side, it has been possible now to create the preconditions for improved control of vibrations resulting from the drive torque and a rising-up of rear-axle transmission and rear-axle support.
Furthermore, the forces induced by the drive torque cannot bring about shifts in the flexibly supported rear-axle support causing steering movements, since the isolation of at least the output-side transmission supporting base from the rear-axle support has the effect that essentially only vertical forces are now introduced into the latter. In addition, any imbalances in the rear-axle transmission and meshing noises of its wheel set are no longer troublesomely transmitted to the rear-axle support.
At the same time, the flexible support bearings for the body-side linking of rear-axle support and rear-axle transmission can be designed specifically to requirements with regard to their movements and oscillations. It is possible for the bearings to be rubber springs or, if appropriate, air springs.
An alternative embodiment of the present invention in which the output-side bearings are arranged coaxially with respect to the rear, body-side flexible support bearings of the rear-axle support offers the advantage of not having to carry out any modifications for supporting the rear-axle transmission on the body side. Thus, it is now possible for the transmission output-side supporting base to be dimensioned favorably for the design of the corresponding support bearings. A presently preferred bearing design is to have the support bearings of the rear-axle support and rear-axle transmission section on a common receiving bolt fixed to the body.
The rear-axle transmission can be flexibly linked on the input side to a front cross member of the rear-axle support. Equally well, however, the input-side support bearing may also be fixed on the body side. Although such a measure requires an alteration on the body side to create a suitable bearing receptacle, it permits a complete detachment of rear-axle support and rear-axle transmission, which leads to optimum results from a vibrational viewpoint, since the rear-axle support and drive train can be completely isolated from each other.